A lemur inspects a pumpkin during a Halloween party in the zoological garden in Dvur Kralove nad Labem, Czech Republic on October 20, 2015. The party is a part of preparation for ''Week of Spirits'' held from Oct. 24 till Nov. 1 in the zoo. (Photo by David Tanecek/CTK via ZUMA Press)

A female cougar is shown in this undated handout photo provided by the United States Fish and Wildlife Service in Okanogan, Washington October 21, 2015. Washington state's governor has overturned a decision by wildlife managers to expand cougar hunting in the Pacific Northwest state, siding with animal rights advocates seeking to protect the solitary felines who are prized by sportsmen. (Photo by Rich Beausoleil/Reuters/U.S. Fish and Wildlife Service)

An Eastern Santa Cruz tortoise, Chelonoidis donfaustoi, is pictured on Santa Cruz Island in the Galapagos Islands in this undated handout photo obtained by Reuters October 21, 2015. Scientists have identified a new species of giant tortoise on the Galapagos Islands, using genetic data to determine that a group of 250 of the slow-moving grazing reptiles was distinct from other tortoise species residing in the Pacific archipelago. (Photo by Adalgisa Caccone/Reuters)

Daria Zhirnova, an employee of the ornithological department of the Royev Ruchey Zoo, feeds Sapa, young female Asian peregrine falcon, also known as Sapsan in Russia during a training session outside the Siberian city of Krasnoyarsk, Russia, October 21, 2015. Sapa and its brother peregrine Sky are involved in the zoo project to tame wild animals for research and their interaction with visitors, according to zoo employees. (Photo by Ilya Naymushin/Reuters)

Sky, young male Asian peregrine falcon, also known as Sapsan in Russia, looks on during a training session conducted by employee of the ornithological department of the Royev Ruchey Zoo in Taiga area outside the Siberian city of Krasnoyarsk, Russia, October 21, 2015. (Photo by Ilya Naymushin/Reuters)

Daria Zhirnova, an employee of the ornithological department of the Royev Ruchey Zoo, releases Sapa, young female Asian peregrine falcon, also known as Sapsan in Russia during a training session outside the Siberian city of Krasnoyarsk, Russia, October 21, 2015. (Photo by Ilya Naymushin/Reuters)

An endangered painted keelback snake seen basking in wetlands in Kolkata, India on October 20, 2015. (Photo by Avrajjal Ghosh/Barcroft India)

A Sumatran Orangutan looks out from its cage before being released into the wild by the Sumatran Orangutan Conservation Programme (SOCP) organization in Jantho forest, Aceh, Indonesia 21 October 2015. Sumatran orangutans (Pongo abelii) are a distinct species and listed as Endangered by the World Conservation Union (IUCN) on their Red List of Threatened Species. The Sumatran orangutan is considered the more immediately in danger of extinction, with only around 6,600 or so left in the wild today, and is therefore classified as Critically Endangered. The species is also listed on Appendix 1 of the Convention on International Trade in Endangered Species (CITES), under which animals smuggled out of their natural range country and confiscated should whenever possible be repatriated and returned to the wild. (Photo by Hotli Simanjuntak/EPA)

A picture made available on 21 October 2015 shows grey geese landing on a meadow in the Lewitz nature conservation area near Friedrichsmoor, Germany, 20 October 2015. The natural reserve that spans 16,800 hectares serves as a resting area for thousands of migrating birds in spring and autumn. (Photo by Jens Buettner/EPA)

The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

Female Gorilla Kathi reaches into a pumpkin carved with a Halloween face and filled with oats and nuts in the Adventure Zoo in Hanover, Germany, October 22, 2015. (Photo by Holger Hollemann/EPA)

The 'birthday girl', a female loggerhead turtle (Caretta caretta) swims past a diver in the 350,000-litre turtle aquarium at the marine museum in Stralsund, Germany, October 20, 2015. The turtle celebrated her 50th birthday today, with a cake made of salad, squid and pollack. (Photo by Stefan Sauer/EPA)

An eagle flies past trees changing color along the Walkill River near New Paltz, New York on Saturday, October 24, 2015. (Photo by David Handschuh)

A squirrel monkey eats in its enclosure at the Zoo in Berlin on October 18, 2015. The German capital saw temperatures rising into the double figures with some sun after a week with unseasonal cold weather and rain. (Photo by Odd Andersen/AFP Photo)

A lion plays with a carved pumpkin during the Fort Worth Zoo's 24th annual Halloween celebration "Boo at the Zoo," Thursday, October 22, 2015, in Fort Worth, Texas. Meat filled carved pumpkins were placed with the Zoo's African lion display for the big cats to play with and explore. (Photo by L.M. Otero/AP Photo)

In this October 8, 2015 photo provided by Jackie Curts are three African lion cubs born at the Indianapolis Zoo. Zoo officials said Tuesday, October 20, 2015, that the one female and two male cubs, born September 21 to first-time parents, mother Zuri and father Nyack, are nursing well and growing. They are expected to make their public debut next spring. (Photo by Jackie Curts/Indianapolis Zoo via AP Photo)

A three week old male Black Rhino calf at Howletts Wild Animal Park near Canterbury in Kent, UK on October 19, 2015 as he becomes the first baby rhino to be born in the park&Otilde's 40-year history. (Photo by Gareth Fuller/PA Images/Startraksphoto)